Windows Server 2012 Essentials cannot be upgraded to Windows Server 2012 R2 Essentials. You can choose to install a new copy of Windows Server 2012 R2 Essentials instead, but this is different from an upgrade, and does not keep your files, settings, and programs. You’ll need to reinstall any programs using the original installation discs or files. To save your files before installing Windows, back them up to an external location such as a CD, DVD, or external hard drive. To install a new copy of Windows Server 2012 R2 Essentials, click the Back button in the upper left-hand corner, and select “Custom (advanced)”.